The starsurge conditions are:
actions.single_target=starsurge,if=buff.lunar_empowerment.down&(eclipse_energy>20|buff.cel estial_alignment.up)
actions.single_target+=/starsurge,if=buff.solar_empowerment.down&eclipse_energy<-40
actions.single_target+=/starsurge,if=(charges=2&recharge_time<6)|charges=3
In English, the sim will Starsurge if:
1. There are no active Lunar Empowerment charges and Eclipse is above 20 energy on Lunar side, or Celestial Alignment is active.
2. There are no active Solar Empowerment charges and Eclipse is above 40 energy on Solar side
3. There are 2 available Starsurge charges and less than 6 seconds until the next charge becomes available.
In short, yes the bot will Starsurge on the downswing of eclipse, but it is not explicitly programed to do so. It will simply do so if one of the above scenarios is true at that given moment.
In order to explicitly do so, you could add the following conditions:
actions.single_target=starsurge,if=eclipse_energy<50&eclipse_change<5
actions.single_target=moonfire,if=remains<15&eclipse_energy<20
The result is that as soon as the downswing of Lunar eclipse passes 50 energy, the bot will prioritize a Starsurge, refresh moonfire in the next GCD (every other cycle thanks to our "if=remains<15" clause) and then begin casting wrath for the eclipse transition.
Now, I'd hardly call myself an expert - far from it. But from what I know it seems like that would do the trick.