I was so excited to spot this last night. This is not an orchid I expected to see blooming any time soon (its roots were in pretty bad shape). I am really hopeful that the flower spike takes, as it is probably my favorite among my plants. It aborted a flower spike last year due to poor potting conditions, so here's hoping that this time I'll do better.
I'm not sure what triggered it--perhaps the apartment has been a little colder, or that I changed my watering style to be more conservative. Now that the spike is there, I will be watering the oncidium with a low nitrogen bloom booster fertilizer, but otherwise trying to keep the conditions as stable as possible.
One interesting note is that this spike showed up really suddenly. Just a couple days ago I was looking at the wrinkling on the little leaf with concern (a sign of dehydration/root issues) and there was no sign of the spike. I'll be keeping close tabs as the spike grows and develops over the next several weeks.
Edit 3/28: Now blooming!
EDIT 3/29: Identified as Wilsonara Pacific Perspective!