This type of thing doesn't actually use RegEx: Try:
Sub ScratchMacro() 'A basic Word macro coded by Greg Maxey Dim oRng As Word.Range Set oRng = ActiveDocument.Range With oRng.Find .Text = "([0-9]{1,})( )(l[!a-z])" .Replacement.Text = "\1" & Chr(160) & "\3" .MatchWildcards = True .Execute Replace:=wdReplaceAll End With End Sub