Brochu Lake was named after Michel-Delphis Brochu and the toponym "Lac Brochu" was formalized in 1986.
This hydronym, which was formalized in 1935 by the Quebec Geographical Commission, evokes the work of life of Michel-Delphis Brochu (Saint-Lazare-de-Bellechasse, Quebec, 1853 - Quebec, 1933), doctor and professor at the Faculty of Medicine of Laval University. The toponym "Lac Brochu" was formalized on December 18, 1986, by the Commission de toponymie du Quebec. 
