diff --git a/hledger-lib/Hledger/Utils/String.hs b/hledger-lib/Hledger/Utils/String.hs
index b6fdaf61a..d6a23b007 100644
--- a/hledger-lib/Hledger/Utils/String.hs
+++ b/hledger-lib/Hledger/Utils/String.hs
@@ -64,7 +64,7 @@ strip = lstrip . rstrip
 
 -- | Remove leading whitespace.
 lstrip :: String -> String
-lstrip = dropWhile (`elem` " \t") :: String -> String -- XXX isSpace ?
+lstrip = dropWhile isSpace
 
 -- | Remove trailing whitespace.
 rstrip :: String -> String