"thunderbolts quivered with elfin flares of heat lightning"
"the fey quality was there, the ability to see the moon at midday"

"she was an elfin creature--graceful and delicate"
"obsessed by things elfin and small"

"elfin bells"
"all the little creatures joined in the elfin dance"

"perpetrated a practical joke with elfin delight"
"elvish tricks"