TikZ : how to control the paths ?

Question

I have a problem with my paths in tikz, as I try to show in the picture :

By using my path as -| or |- I can obtain the two green paths, but I would like to have the red one, and neither |-| or || are defined.

Here is my code

\documentclass{article}
\usepackage{tikz}

\tikzstyle{block4} = [rectangle, draw, fill=cyan!8, text width=6cm, text centered, rounded corners, minimum height=4em]
\tikzstyle{through} = [rectangle, fill=white, text width=6cm, text centered, rounded corners, minimum height=4em]
\tikzstyle{block5} = [rectangle, draw, fill=yellow!8, text width=6.5cm, text centered, rounded corners, minimum height=4em]
\tikzstyle{block6} = [rectangle, draw, fill=green!8, text width=6cm, text centered, rounded corners, minimum height=4em]
\tikzstyle{block7} = [rectangle, draw, fill=blue!8, text width=6cm, text centered, rounded corners, minimum height=4em]

\begin{tikzpicture}[node distance = 2cm, auto]
\centering
% Place nodes
\node [block4] (Foyer) 
        {\emph{table foyer.foyer} \\
        \begin{itemize}
        \item sous-table par département
        \item suppression doublons
        \end{itemize}
        };

\node [block4, right of=Foyer, node distance=7cm] (Pote) 
        {\emph{table pote.dep} \\
        \begin{itemize}
        \item  choix anrev correct
        \item  doublons dirindic
        \end{itemize}
        };


\path (Foyer) -- (Pote) node[through, pos=.5,below=1cm] (Merge1) 
        {\textbf{Fusion par dirindik}
        };


\node [block5, right of=Merge1, node distance=14cm] (Indrev) 
        {\emph{table foyer.indrev}
        \\ \begin{itemize}
        \item détermine, via MDS, âge, persfipd
            \begin{itemize}
            \item dirindik(N-1)
                \begin{itemize}
                \item valeur
                \item "inconnu anprec"
                \end{itemize}
            \item persfip(N-1)
            \end{itemize}
        \end{itemize}};


\node [block4, below of=Merge1, node distance=1.5cm] (FoyerPote) 
        {\emph{table Travail.FoyerPoteDEP} \\
        \begin{itemize}
        \item  on empile chaque département
        \end{itemize} 
        \emph{table Travail.FoyerPoteFR}
        };

\node [block7, below of=FoyerPote, node distance=2.5cm] (IRFoyer) 
        {\emph{table Travail.FoyerPote nationale} \\
        \begin{itemize}
        \item  On récupère les variables idoines
            \begin{itemize}
            \item les MDS année précédente
            \item l'impôt
            \item les var pour REVDISP(N)
            \end{itemize}
        \end{itemize} 
        }; 

\path (Merge1) -- (Indrev) node[through, pos=.5,below=6cm] (Merge2) 
        {\textbf{Fusion par dirindik}
        };

\node [block6, below of=Merge2, node distance=1.5cm] (IndivPote) 
        {\emph{table Travail.FoyerPote par dep} \\
        \begin{itemize}
        \item  on empile
        \end{itemize} 
        \emph{table Travail.FoyerPote nationale}
        };        


% Draw edges
\path [line] (Foyer)  -|  (FoyerPote);
\path [line] (Pote) -| (FoyerPote);
\path [line] (FoyerPote) -- (IRFoyer);
\path [line] (IRFoyer) -| (IndivPote);
\path [line] (Indrev) -| (IndivPote);

\end{tikzpicture}
\end{document}