I couldn't come across anything on their Facebook page or their website with an exact time so my next best guess would be sundown or right before.
The lights maybe on all the time but I was suggest you get there after sunset so you can enjoy the lights when its dark out.
They seem to be on a PEC so they come on at dusk.
Dusk
5 pm
I think 6pm
When it gets dark out
After dusk
I don't know you will have to call them
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