During 1910-12, Lacasse intuitively established his search for light, extracted from the glistening rock. In 1925, Lacasse moved to Paris where he became known as a painter of religious scenes. However, with Brancusi as his neighbour, Lacasse was inspired to revisit his teenage interest in light and the composition of rocks - this led him to make a series of small abstract paintings during the 1930s. His acquaintance with Robert Delaunay influenced his coloristic development. Upon his return to Paris in 1946, after having spent the war years in Britain, Lacasse had been overshadowed by Serge Poliakoff, who admitted having learnt much from Lacasse during the late 1930's during his visits to Lacasse's Montparnasse's gallery 'l'Equipe'. In response, Lacasse painted a series of ambitious works, large in size and intense in the chromatic variations of one colour.

The works of Lacasse are included in the following museums: Musée d'art moderne de la Ville de Paris, Paris; Musée national d'art Moderne, Centre Pompidou, Paris; Musée des Beaux-Arts, Brussels; Musée de Tournai, Tournai; Tel Aviv Museum of Art, Tel Aviv; Eilat Museum, Eilat; Carnegie Institute, Pittsburgh; National Gallery of Victoria, Melbourne.