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Your plant sounds easily big enough to flower. When big Oncidiums don't flower the usual causes are one or more of: Not enough light, irregular watering or not fertilizing at all.
Leaves should be pale green in good light, not dark green in less light. If you have any transverse pleats in the leaves that indicates not enough water. They need some fertilizer, but not much.
The time to divide is when new growth is forming and new roots are just beginning to show. If you wait too long the longer new roots will be damaged in the repot, and the plant will be set back. So if your plant is starting new roots you could divide it.
However, if you have the space, larger plants give better displays. 10 pseudobulbs is not terribly large for an Oncidium. If it hasn't been repotted in 2 years or more I would repot as soon as it makes new roots. If it's been repotted within 2 years I would leave it in that pot and try changing other things to get it to flower.
What kind of light is it getting? What are your day/night temperatures? How is it potted? How are you watering and fertilizing?
One or more photos of the whole plant would help. Sometimes people need to make 5 posts before posting photos. If that's your situation each response to somebody else's post counts.
Edit: I looked it up on Orchid Roots (bluenanta.com.) The current name is
Oncostele Eye Candy. It sure is pretty! Its grandparent Oncidium Barossa Valley is composed of cool growing species. If your temperatures are fairly warm, you might try keeping this one cooler.