There is a world of difference between ‘Postponing’ elections (indefinitely) and canceling them outright.
I would tend to agree that the outright canceling of elections would be a major tipping point.
But postponing them for little while .. until the powers that be consolidate their power might not be the same thing…. Their story could be that “we’re just doing this until the emergency is over”… and keep it on doing it until it’s advantageous for them to have them again.
(Even a Socialist Worker’s party lead by Hitler had elections – massively skewed they were – but they had them none the less)
If the election doesn't happen on schedule the Zombie Apocalypse starts. They know it. They'll retain their fig leaf to keep the people complacent, and believe that they continue to live in a "democracy".