diff --git a/Lib/argparse.py b/Lib/argparse.py
index ddfd772..b3284f9 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1897,7 +1897,9 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
                     # arguments, try to parse more single-dash options out
                     # of the tail of the option string
                     chars = self.prefix_chars
-                    if arg_count == 0 and option_string[1] not in chars:
+                    if (arg_count == 0 and
+                        option_string[1] not in chars and
+                        explicit_arg is not ''):
                         action_tuples.append((action, [], option_string))
                         char = option_string[0]
                         option_string = char + explicit_arg[0]