In the 20 ridings with the highest proportion of visible-minority voters — ridings where the vis-min population ranges between 52% and 90% — the Conservative vote was higher in 2008 than in 2006 in 19 of those ridings. The Liberals held 17 of those ridings after 2006 and lost only two this year. But with only one exception, the Liberal lead shrunk in every riding they managed to hang onto.
Expand the sample: Add ridings 21-40 by proportion of visible-minority voters. This takes us to Saint Léonard-St. Michel, where 35% of the voters belong to visible minorities. In this second tranche of 20 ridings, the Conservative share of the vote increased in 18. (One was the riding where Art Hanger retired after 15 years. The other was Justin Trudeau’s riding.) The Conservatives gained two of these ridings. Most of these ridings began and stayed Liberal; in all but one case, the Liberal lead decreased in ridings they did hang onto.
So in the top 40 ridings by proportion of visible-minority voters, the Conservative vote increased in 37. I got my information for this analysis here.