Hi Carol,
They came out as mono cloves, because they wanted another season to grow. Elephant Garlic if its not under optimal conditions, or as it grows from various stages, will persist as a mono clove of various size, until the mono clove reachs its maximum size within the proper season for division and maturity. My guess is the cloves were very small, or they didn't have the best growing conditions to reach maximum size this year. If your in a mellow climate, like I've seen in zone 8, they will start growing in early fall, only being dormant after they start growth, for about a month in peak winter, then continuing that growth in late winter, early spring. So planting them late or being in a place with harsh winters or less then optimal growing conditions from any factors, can all drastically slow their development, and time to reach maturity.
When to plant or replant them will depend on your hardiness zones. In zone 8b, they grow as
perennial, so anytime they are dormant is ok to plant, and planting later just slows their growth for that harvest season. They will rest when they go dormant in the dry, and put up their growth when they are ready, typically when they come out of the dry if no
irrigation is being used. If you fall planted, I would just let them keep growing untill they get mature, but also search out the bulblets: and plant them too. You'll eventually end up with more garlic then you can use, and mono bulbs of any size are still good to eat. Under your conditions, it may take 2 years for cloves to reach maturity, and 4 years for bulblets to mature; however, all stages of mono clover are good to use, and they will typically have bulblets sometimes called bulbils growing under them. The larger the Elephant garlic plant, the more bulblets they will have, even adding more through each season of growth.
Hope that helps!