He might or might not want to. It's not hard to imagine a situation in which a seat becomes vacant a fairly short time before royal assent is anticipated on the bill. It might or might not be reasonable. I'm not actually trying to figure if it would be reasonable—that's a political consideration. I'm wondering about....
Evidence of meeting #106 for Procedure and House Affairs in the 42nd Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was elections.
A video is available from Parliament.