Curling is usually caused by one of three things,
1) herbicide drift (from spraying weeds nearby)
2) insect invasion
3) drought

So check to see if your neighbors have sprayed any weeds lately. Then inspect the plant for insects, then make sure it has plenty of water. It may be too late, but you can check the roots and see if they are healthy. If so, you may want to cut off the curled foliage and let the bulb generate more.

You could check for spider mites also. Elephant ears seem prone to these pests. Look for the webs.

If you have spider mites, to treat, spray leaves and soil with insecticidal soap. Repeat a few days later.