Isn't this OTL after the Quiet Revolution? I get that this is in pre-1900 rather than post-1900, but my point is that we just need to get the OTL backlash against Church control to happen sooner.
TBH, I think the only reason that Quebec remained conservative for so long was:
1. Catholicism was a core part of Quebecois identity vis-a-vis anlgo Canada.
2. The secular education system and the merchant classed (traditional supporters of 19th-centiury liberalism) we dominated by anglo-Montrealers.
Here's a sketch of a TL:
- France is somehow able to hold on to both Canada and Louisiana in the Seven Years' War.
- this postpones the American Revolution until the early 19th century
- butterflies change the course of the French Revolution to result in a more moderate republic while allies itself with Britain, but not before the French Royal family flees to French North America.
- with Canada independent, the American colonists no longer feel they need British protection and they revolt while Britain is fighting Austria, Prussia and Russia. The newly independent alt-USA allies itself eith monarchist French North America.
- Montreal grows as the hub of French Noeth America into an industrial city. The business classes of Montreal chafe under the conservative monarchy. Without every being a British colony the Quebecois don't turn to Catholicism to define their identity and instead aspire to be more like republican France
- in the mid-19th century, once the alt-USA no longer fears Britain, they sponsor a liberal revolution in French North America whoch results in a liberal, secular Quebec defining itself in opposition to a more conservative, rural Louisiana