A graduate in agronomy from the Institut agricole d’Oka (Quebec), Lalonde ran the family poultry farm A.O. Lalonde, in Bourget, and became the owner of the operation in 1933. He was recruited to be the president of the UCFO, a position he held from 1935 to 1945. In 1936, he organized a general congress on co-operation witch lead to the establishment of credit unions and co-operatives, namely the Dairy co-operative and the Poultry co-operative in Bourget. He was the head of the Prescott-Russell Federation of Agriculture. During his ten years as president of the UCFO, he recruited members, ensured they received training, and worked at the official recognition of the organization, which obtained its provincial charter in 1945. In 1936, he wrote the UCFO’s first editorial in the agricultural page of Le Droit, writing under the pseudonym of Nicodème (1936-1946).
In late 1946, the UCFO launched its first newspaper, La Terre Ontarienne. In 1947, Lalonde was called upon to run the publication and act as the secretary-general of the organization. Under the pseudonym of “Jean Nackroche”, he wrote several editorials and articles in the section “Aux Accros” of the newspaper. He also founded the weekly publication Françario. He was actively involved in several farm organizations, including the dairy and poultry co-operatives in Bourget, and he did volunteer work in the community. He also produced the souvenir book for the 100th anniversary of Bourget. Grand commander of the Ordre de Jacques-Cartier, he was dedicated to different causes such as the advancement of Francophones, cooperation and volunteer work.