Here your are. Create your dimstyle first, name it "LeaderArrow". Make sure that this style is always in the drawing.
You didn't say whether your leader should have 3 point or just 2. Erase the blue PAUSE it the later.
(defun c:LeaderArrow ( / *error* oDIMSTYLE)
(defun *error* (errmsg)
(if (not (wcmatch errmsg "Function cancelled,quit / exit abort,console break,end"))
(princ (strcat "\nError: " errmsg)))
(command-s "_.DIMSTYLE" "_Restore" "LeaderArrow" oDIMSTYLE)
(princ))
(setq oDIMSTYLE (getvar 'DIMSTYLE))
(if (tblsearch "DIMSTYLE" "LeaderArrow")
(command "_.DIMSTYLE" "_Restore" "LeaderArrow"
"_.LEADER" PAUSE PAUSE PAUSE ;; erase last PAUSE if you want to have 2 points only
"_Annotation" "" "_none")
(princ "\nError: There is no 'LeaderArrow' style in the drawing."))
(*error* "end")
)