The first year I grew them, the Soleils d'Or put on a great display, but this year one or two of them did not flower. They produced plenty of leaves but no flowers, a condition known as "blindness". Researching this I found that I had not been treating the bulbs properly after flowering.
THIS, however is Best Practice:-
1. Remove the old flower-heads, and do not let them set seed. Setting seed reduces the vigour of the parent plant.
2. Do not cut off or (worse) tie in knots, the leaves. Let them die down naturally, returning their energy to the bulb.
3. Feed the bulbs a couple of times with a general-purpose fertiliser.
4. Keep the bulbs moist (i.e. water the pots) until the foliage has died down.
5. When the foliage has all gone dry and brown, lift the bulbs, clean them off, and store them somewhere dry, cool and dark until ready to plant them again. (Protect from mice!)
I shall be following this advice myself this year, so I look forward to seeing the results next Spring.