I heard on the CBC that Harper is still MP for 10 days and Justin will take over after. But, Harper stepped down yesterday and the conservatives will be looking for a new leader now.
As a Montrealaer, I'm pretty glad the MP is from my hometown. Historically, it always meant more good things for the city. (Shawinigan would be even more of a shit whole if it wasn't for Jean Chrétien back in the day)