"After the hospital thing..." indicates to me that it wasn't the same night. In that case Tessio would have said something like: "Sonny got mad last night."
As we do in so many cases, we have to go to the novel for guidance.
Michael wakes up in the morning and Tom tells him, among other things, that after what happened at the hospital, Sonny got hard and that we we got up on the scoreboard ... four o'clock this morning.
So, there's no indication that any more than about six hours passed between Mike's encounter with McCluskey and Bruno's murder. So, it doesn't seem that there could have been any planning involved and luck seems a stretch since the hierarchy of the Tattaglia family would not have been exposing themselves.
