Ice Time Frozen Orb explosion tracking

[Xo1o]

I'd like to create a Weakaura that triggers upon Frozen Orb first hitting a target, which then should give me a static 10 sec countdown timer until the orb explodes into Ice Time's Frost Nova after its duration is up.

There are two problems with this:
- I can't just track the cooldown of Frozen Orb, since it's dynamically reduced by Blizzard, and this timer would be less accurate anyway once the orb is cast from further away (the cooldown starts to count down immediately, but the orb only becomes active for its 10sec duration after reaching a target)
- creating a combat log trigger that checks for the Orb dealing damage actually works exactly how I want it to.... but it resets the timer with every further damage tick


tl:dr I want a static 10sec countdown to know exactly when Ice Time explodes Frozen Orb in order to shatter off of the nova. Can this be done?