diff --git a/lisp/dired-aux.el b/lisp/dired-aux.el
index c3b8373e610..c537c2e458f 100644
--- a/lisp/dired-aux.el
+++ b/lisp/dired-aux.el
@@ -164,8 +164,12 @@ Uses the shell command coming from variables `lpr-command' and
   (let* ((file-list (dired-get-marked-files t arg))
 	 (command (dired-mark-read-string
 		   "Print %s with: "
- 		   (mapconcat 'concat (append (list lpr-command)
- 					      lpr-switches) " ")
+ 		   (mapconcat 'identity
+			      (cons lpr-command
+				    (if (stringp lpr-switches)
+					(list lpr-switches)
+				      lpr-switches))
+			      " ")
 		   'print arg file-list)))
     (dired-run-shell-command (dired-shell-stuff-it command file-list nil))))