As Jubobs says, your question is extremely vague. I'm not sure what you mean by horizontally exactly - horizontally at the top? In the centre? Top and bottom? At the edges? In the middle? Etc.
Still, you should be able to adapt the following:

\documentclass{article}
\usepackage[paper=a4paper, verbose, centering]{geometry}
\usepackage{pgfornament}
\newcommand{\corner}[1]{%
\begin{tikzpicture}[remember picture, overlay]
\node[anchor=north west] at (current page.north west){%
\pgfornament[width=2cm]{#1}};
\node[anchor=north east] at (current page.north east){%
\pgfornament[width=2cm,symmetry=v]{#1}};
\node[anchor=south west] at (current page.south west){%
\pgfornament[width=2cm,symmetry=h]{#1}};
\node[anchor=south east] at (current page.south east){%
\pgfornament[width=2cm,symmetry=c]{#1}};
\end{tikzpicture}%
}
\newcommand{\cornerplus}[2]{%
\begin{tikzpicture}[remember picture, overlay]
\node[anchor=north west] at (current page.north west){%
\pgfornament[width=2cm]{#1}};
\node[anchor=north east] at (current page.north east){%
\pgfornament[width=2cm,symmetry=v]{#1}};
\node[anchor=south west] at (current page.south west){%
\pgfornament[width=2cm,symmetry=h]{#1}};
\node[anchor=south east] at (current page.south east){%
\pgfornament[width=2cm,symmetry=c]{#1}};
\node[anchor=north] at (current page.north){%
\pgfornament[width=6.5cm,symmetry=h]{#2}};
\node[anchor=south] at (current page.south){%
\pgfornament[width=6.5cm]{#2}};
\end{tikzpicture}%
}
\newcommand{\pt}[1]{%
\begin{tikzpicture}[remember picture, overlay]
\node[anchor=north] at (current page.north){%
\pgfornament[symmetry=h]{#1}};
\node[anchor=south] at (current page.south){%
\pgfornament[symmetry=h]{#1}};
\end{tikzpicture}%
}
\title{Title}
\author{Author}
\date{}
\usepackage{kantlipsum,titling}% for demo only
\begin{document}
\maketitle\corner{31}\thispagestyle{empty}
\clearpage%
\maketitle\cornerplus{61}{85}\thispagestyle{empty}
\clearpage%
\maketitle\cornerplus{63}{85}\thispagestyle{empty}
\clearpage%
\maketitle\pt{84}\thispagestyle{empty}
\clearpage%
\maketitle\pt{71}\thispagestyle{empty}
\clearpage%
\maketitle\pt{87}\thispagestyle{empty}
\clearpage%
\end{document}
Update
Although pgfornaments does not really seem to feature decorations which are designed to 'fit together' or link in the way some decorative fonts do, for example, if you select ornaments carefully, you can create this sort of effect. I found that the best choices were squarish ornaments because you can easily slot them into nodes on chains in a tikzpicture. For example:

\documentclass{article}
\usepackage[paper=a4paper, verbose, centering]{geometry}
\usepackage{pgfornament}
\usetikzlibrary{chains}
\title{Title}
\author{Author}
\date{}
\usepackage{titling}% for demo only
\begin{document}
\maketitle
\begin{tikzpicture}[remember picture, overlay, start chain, node distance=-2mm]
\node (nworn) [shift={(5mm,-5mm)}, anchor=north west, on chain ] at (current page.north west) {\pgfornament[width=10mm]{7}};
\foreach \i in {1,...,17}
\node [on chain] {\pgfornament[width=10mm]{7}};
\node (neorn) [on chain] {\pgfornament[width=10mm]{7}};
\foreach \i in {1,...,25}
\node [continue chain=going below, on chain] {\pgfornament[width=10mm]{7}};
\node (seorn) [on chain] {\pgfornament[width=10mm]{7}};
\foreach \i in {1,...,17}
\node [continue chain=going left, on chain] {\pgfornament[width=10mm]{7}};
\node (sworn) [on chain] {\pgfornament[width=10mm]{7}};
\foreach \i in {1,...,25}
\node [continue chain=going above, on chain] {\pgfornament[width=10mm]{7}};
\end{tikzpicture}
\thispagestyle{empty}
\clearpage
\maketitle
\begin{tikzpicture}[remember picture, overlay, start chain, node distance=-2mm]
\node (nworn) [shift={(10mm,-10mm)}, anchor=north west, on chain ] at (current page.north west){\pgfornament[width=10mm]{61}};
\foreach \i in {1,...,8}
{\node [on chain] {\pgfornament[width=10mm]{62}};
\node [on chain] {\pgfornament[width=10mm]{61}};}
\node (neorn) [on chain] {\pgfornament[width=10mm]{62}};
\foreach \i in {1,...,12}
{\node [continue chain=going below, on chain] {\pgfornament[width=10mm,symmetry=h]{62}};
\node [continue chain=going below, on chain] {\pgfornament[width=10mm]{62}};}
\node (seorn) [on chain] {\pgfornament[width=10mm,symmetry=h]{62}};
\foreach \i in {1,...,8}
{\node [continue chain=going left, on chain] {\pgfornament[width=10mm,symmetry=h]{61}};
\node [continue chain=going left, on chain] {\pgfornament[width=10mm,symmetry=h]{62}};}
\node (sworn) [on chain] {\pgfornament[width=10mm,symmetry=h]{61}};
\foreach \i in {1,...,12}
{\node [continue chain=going above, on chain] {\pgfornament[width=10mm]{61}};
\node [continue chain=going above, on chain] {\pgfornament[width=10mm,symmetry=h]{61}};}
\end{tikzpicture}
\thispagestyle{empty}
\clearpage
\end{document}
pgfornmanentsspecifically? There are plenty of decorations which are designed for this so it seems a little strange to insist on using ones which are not. The ornaments you've chosen in your example seem clearly not to complement each other stylistically in any case. – cfr Mar 29 '14 at 22:43