This was initially reported as if it was true by the mainstream media, who have their preconceptions. However, if you look at this page here you may see that once they analyzed the statistics that did not turn out to be the case.
The New York Times posted an article here that confirms that (BTW -- you can log in as "hillary/hillary"):
Here are the facts. As Andrew Kohut of the Pew Research Center points out, there was no disproportionate surge in the evangelical vote this year. Evangelicals made up the same share of the electorate this year as they did in 2000.