Hi,
I don’t know the correct way to do it, but there’s a few workaround you can do
1- Have the particle opacity to 0 for the time being, and in the update check if time is less than your delay, when it switches to after the delay, add velocity, etc. like you would do normally and set a boolean variable to make those one time event trigger only once.
2- Use a middle man emitter, with no particle update and no renderer. This one receive your Emitter 1, particle lifetime of the delay you want, generate new death event, Emitter 2 receive that event.
Those are probably not the best answer, but as you haven’t have an answer in 4 days, thought that might help. Option 1 is probably better performance wise but more complex to setup.