I think he'll put it off as long as he can. Maybe oil prices will surge. Maybe a war will be declared and harper will join it and cancel the election. Maybe the Duffster will have a heart-attack. Maybe Patrick Brazeau will lose some weight and get back in shape and beat-up Justin Trudeau on the streets of Ottawa.
Or maybe (he can only hope!) there will be a horrible terrorist attack, killing several Canadians, and we'll all flock to harper (who let it happen) to "keep us safe"!
Or maybe another train will derail. Or another deadly listeriosis outbreak. Or a financial sector implosion!
I guess, in the final analysis, harper is a consistent coward. When such a creature has no good options, what he tends to do is keep his head down and hope for the best.