Yes, but where was the dark and the light? "Dividing" them does not have to mean they alternate. It says nothing about daylight shining on the Earth until verse 16:
16 And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also.
Precisely my point, there was clearly another mechanism at work before that, which I think has much more to do with John 1:5.
15 The light shines in the darkness, and the darkness has not overcome it.
This is speaking of a spiritual Light vs the "dark side", not about visible photons.
Whether the sun did not exist or did exist as a dormant invisible object is all the same. Either way there was no daylight as we know it in those earlier verses.