Here's some of the spelling variations I've found so far:
DALGARNO , DELGARNO , DALGAIRDEN , DALGALMO , DALGAIRN , DALGAIRNS, DALGAIRNE, DALGAIRNO , DALGAIRNER , DALGARDDO , DALGARDEN , DALGARDENS , DALGARDIN, DALGARDINE , DALGARDN , DALGARDNER , DALGARDNO , DALGARDNOE , DALGARNE , DALGARN , DALGARNER , DALGARNIE ,DALGARNOE , DALGARNOT, DALGARNS , DALGARRDNO