Most voters are politically motivated in our era by specific issues & personalities but not very much by political Parties (except insofar as a Party is rejected).  This is especially (but not uniquely) so in Quebec.

Notable is the emergence over the past decade of a 'progressive' block of 20%+ of Canadian voters (including in Quebec) that reject the Conservative Party but will swing between the Liberals & NDP on the basis of the factors described in my first paragraph. There is an analogous additional 'nationalist' block of Quebec voters that reject the Liberals but shift between the BQ & NDP.

Under Trudeau,  this Canada wide NDP/Liberal shift is optimised & Quebec Liberal rejection factor minimised to the Liberal's advantage impacting the NDP hard & limiting Conservative prospects as well.

The Liberal hold on this progressive block of voters may well weaken (& the Quebec nationalist block shift) all to the net gain of the NDP as the next General Election approaches.