The Quebec government maintains a website on all the place names in the province. If you check it out at www.toponymie.gouv.qc.ca and look at how Lake Louisa got its name, you will find two and a half somewhat conflicting stories. In one, they describe a talented musician named Louisa M. Holland who performed for some surveyors in the 1840's and they subsequently named the lake in her honour. In the second, there is the sad story of Louisa who drowned in the lake near the outflow in the early 1800's, and in the half- story, it goes on to say that the lake was called Lac Louise between 1970 and 1984 after Louise Lafleur who often fished off a rock that dominated the lake. It does not say when she lived, or why the lake would have been named for her. It leaves one going back over and checking the date. 'Did they mean 1970 or 1870?' But it seems they meant 1970.
For the entire article, click here: https://www.ballyhoo.ca/scottish-irish-influences.html