split-string

CL-USER> (loop with input-string = "abNandrRpQ"
               with current-string = ()
               for i across input-string
               do (push i current-string)
               when (upper-case-p i)
                 collect (coerce (reverse current-string) 'string)
                 and do (setf current-string ()))


("abN" "andrR" "pQ")