domwass' solution has one problem: In the bibliography, author names will be typeset without the prefix at the start, but sorting will still use the name prefix. So I suggest to a) set useprefix=false when loading biblatex b) use domwass' hack to set the underlying toggle to true at the begin of the document c) use the hack again to set it to false at the begin of the bibliography.
\documentclass{article}
\usepackage[useprefix=false,style=authoryear]{biblatex}% "useprefix=false" is the default
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@misc{A01,
author = {de Author, A.},
year = {2001},
title = {Alpha},
}
@misc{B02,
author = {Buthor, B.},
year = {2002},
title = {Bravo},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\nocite{*}
\makeatletter
\AtBeginDocument{\toggletrue{blx@useprefix}}
\AtBeginBibliography{\togglefalse{blx@useprefix}}
\makeatother
\begin{document}
Some text \autocite{A01,B02}.
\printbibliography
\end{document}