The Lucerne (from 2006 through 2011) replaced both the upscale LeSabre, and top of the line, Park Avenue. Well, if you're naming a car for a place, and you are replacing Park Avenue... why go with a Swiss city? There is also a large dairy by the name of Lucerne

 And then the Lucerne was replaced with the LaCrosse... a hockey stick game, (the city in Wisconsin has a space after the La and before Crosse, but was preceded by the LaSabre. Maybe someone in the naming process was stuck on the words beginning with L that have no meaning? That sound French?

Braking was not one of the Lucerne's strong points, as testing revealed stopping distances that were the longest in the full-size sedan class, as it's bigger than a Chrysler 300

A LaSabre is a sword, a LaCrosse is a stick for the purpose of catching a ball (the crosse)

https://www.edmunds.com/buick/lucerne/
http://www.caranddriver.com/features/rides-for-the-retirement-set-buick-lucerne-page-3

I even sent an email to Buick.com, but I doubt they are going to reply, even if they knew. They are only interested in selling cars, not discussing history