With all the species I have, there's no such thing as a "when they wake up" period. There's always something in the middle of its growing season (like the variabilis that have all just started to grow), or species like the titanums that are entirely aseasonal and may wake up or go dormant whenever they please, for however long they please (and my biggest is about to break its current confines, so it needs an upgrade, badly). You don't want to try forcing them to wake up when they're not ready, otherwise they will rot, so don't water konjac until you see it starting to grow (if you keep it potted, that means until you see something actually sticking up out of the soil). If you want flowers, give them a lot of light, and feed them A LOT. The bigger the tuber gets, the better chance it will decide to bloom, there are no other real triggers.