Although Justin Trudeau and his Liberal Party won the most seats in the October 2015 election, he does not assume his role as Prime Minister until November 4th. In the meantime, Stephen Harper continues his duties as Prime Minister. The Governor General, David Johnston, will invite Justin Trudeau at Rideau Hall (the residence and workplace of the Governor General) to form the next government. Trudeau’s swearing-in ceremony will take place on November 4th and will announce the members of his cabinet on the same day.
You can find out more about the swearing-in of a new ministry at the Governor General of Canada website: http://www.gg.ca/document.aspx?id=314
