IInstructor, builder, fond of alpine and cross-country skiing, Paul Lalonde (1917-1984) had a mission, to revive cross-country trails too often invaded by Nature and, where necesary, to develop new ones. Lalonde’s skiing career is associated for the greater part to the slopes of La Marquise in Saint-Sauveur, to ski teaching as well as the preservation of cross-country skiing strails in the Saint-Sauveur and Morin-Heights regions.