Hey Tolly - don't know if you're still around, but thought I'd reply as you sounded really worried, but quite unnecessarily so, I think.
You say you were scanned on 16 December and there was "one follicle just about to pop on right ovary". So it sounds like you were scanned at about mid-cycle and you were about to ovulate from your right ovary. At that stage in your menstrual cycle it would be quite NORMAL to see nothing significant in the other ovary.
If you had had a 'baseline' scan on day 2 (or between day 2 - 5) you'd expect to see several small antral follicles (about 2-9 mm in diameter) in each ovary. The numbers are variable between women and between cycle to cycle, but say between 9 and 21 follicles across BOTH ovaries (not that number in each ovary!), but could be anywhere between 4 and 35 follicles. (There's a table that explains the range or numbers here for example, if you scroll down the page). Then under the influence of increasing FSH, one follicle grows faster/bigger than the others and becomes the lead dominant follicle. While this happens, the other follicles just fade away (by atresia). Then the lead, dominant follicle ovulates once it reaches between 18 - 24 mm in size.
The description of your left ovary as 'quiescent' (i.e. quiet and still) is, I think, an entirely appropriate term for what you would expect to see on the non-ovulating side at that point in your cycle - plus it tends to be used to describe a temporary, not a permanent state of affairs. Next month you would probably ovulate from your left side and your right ovary would be quiescent mid-cycle. When you asked the sonographer if your left ovary would "come back" I'm guessing she looked confused/doubtful because she thought you meant in the current cycle she was scanning, when of course it won't - you wouldn't expect it to.
The other thing with Clomid (which you probably know already) is that because you're not doing IVF at the moment (and I'm guessing you're doing timed intercourse rather than IUI - although IUI would be similar) your doctors would only want you to develop ONE lead/dominant follicle (and NOT loads, which is the aim with IVF). Otherwise you could risk getting pregnant with a high number of multiples (quintuplets or something) which I doubt you'd want either!
Really don't worry, I'm sure you'll be fine.