0:00 am - 6:00 am - Dawn Bloom
6:00 am - 12:00 pm - Noon Bloom
12pm - 18:00 pm - Dusk Bloom
18:00pm - 0:00 am - Night Bloom
Pretty much no room for discussion allowed on this topic, as this is the original designers' source material we are working with.
(https://wiki.guildwars2.com/wiki/Cycle ) No matter what the recent shuffled in, shuffled out storytellers, or some random lads, trying to sell their own head canon as straight facts, want to make believe in.
As for your own head canon, what cycle your Sylvari belongs to in the end, no matter how weird the circumstances, well, pick and create whatever floats your boat. Your character, your choice, your story. But please don't expect anybody to agree and stick with your version and interpretation.