Well someone seems to have an inside line to Ms Jean and her thinking. The only thing clear to most people is that she suddenly gets to exercise more decision-making power than most GGs. But it's entirely her power.
Harper can ask her to progogue, but she need not accede. If she doesn't, he has to meet the House and it'll be only a short time before he loses a vote which demonstrates he cannot govern.
Of course, if Ms Jean refuses to prorogue he could right then and there ask her to call an election, but that's her decision to make.
Likewise, if he's defeated in the House, and asks for an election, she need not grant his request if she believes there's a better option than another $300 million dollar election likely as indecisive as the last.
Technically, it's her government, and she has a responsibility to ensure there are ministers in place who represent most of the people to do the business of the country.
It's entirely up to her whether the interests of the country would be better served by calling on the NDP/Liberal coalition which has a written agreement with the party representing Quebec, and thereby commands a real majority of the people's elected representatives. Presumably she'll weigh the understandable unhappiness of those who feel the election was decisive and this is somehow moving the goalposts—it wasn't, and it isn't—against the understandable unhappiness of an electorate that just wants the job to be done, not to vote for the fourth time in as many years.
One would hope the Supreme Court would realize that no good purpose would be served by a further delay while the case is argued back and forth and nobody's actually governing. How the difficult decision would be any less unhappy made by nine judges I cannot see.
Entirely legally and properly, the options are an election no one* wants; a coalition government no one expected, or an impotent government on life support no one can afford. We should all be praying for Ms Jean.
*Of course there's the MiniMe Machiavelli Scenario: Unable to win a majority legitimately after three tries, in spite of destroying the Liberal leader and crippling his party, Harper has come up with a way to paint himself and the Conservatives as victims of bullying by those big bad NDP and Liberal bullies, with the Evil Separatists (most of whom have been MPs longer than the Conservatives) piling on. Hopefully "defeated by this cabal before we could save the country" or at worst having to ask for an election, he hopes to finally get his majority on spurious accusations that his elected members are somehow more democratically entitled than those on the other side. Whether he can succeed in this slander, we'll have to see