diff --git a/cssselect/parser.py b/cssselect/parser.py
index a63246b..daeb731 100644
--- a/cssselect/parser.py
+++ b/cssselect/parser.py
@@ -331,8 +331,8 @@ def canonical(self) -> str:
         selector_arguments = []
         for s in self.selector_list:
             selarg = s.canonical()
-            if len(selarg) > 1:
-                selarg = selarg.lstrip("*")
+            if len(selarg) > 1 and selarg[0] == "*" and selarg[1] in "#.[:":
+                selarg = selarg[1:]
             selector_arguments.append(selarg)
         args_str = ", ".join(selector_arguments)
         return f"{self.selector.canonical()}:is({args_str})"
@@ -361,8 +361,8 @@ def canonical(self) -> str:
         selector_arguments = []
         for s in self.selector_list:
             selarg = s.canonical()
-            if len(selarg) > 1:
-                selarg = selarg.lstrip("*")
+            if len(selarg) > 1 and selarg[0] == "*" and selarg[1] in "#.[:":
+                selarg = selarg[1:]
             selector_arguments.append(selarg)
         args_str = ", ".join(selector_arguments)
         return f"{self.selector.canonical()}:where({args_str})"
@@ -521,8 +521,8 @@ def __repr__(self) -> str:
 
     def canonical(self) -> str:
         subsel = self.subselector.canonical()
-        if len(subsel) > 1:
-            subsel = subsel.lstrip("*")
+        if len(subsel) > 1 and subsel[0] == "*" and subsel[1] in "#.[:":
+            subsel = subsel[1:]
         combinator = " " if self.combinator == " " else f" {self.combinator} "
         return f"{self.selector.canonical()}{combinator}{subsel}"
 
diff --git a/tests/test_cssselect.py b/tests/test_cssselect.py
index 07bf58b..5d3efd0 100644
--- a/tests/test_cssselect.py
+++ b/tests/test_cssselect.py
@@ -467,12 +467,19 @@ def css2css(css: str, res: str | None = None) -> None:
         css2css("div:is(*)")
         css2css(":is(*, .foo)")
         css2css(":where(*)")
+        # a namespace wildcard is not a redundant universal selector
+        css2css("foo *|bar")
+        css2css("foo > *|*")
+        css2css(":is(*|foo, bar)")
+        css2css(":where(*|foo)")
         css2css("foo:empty")
         css2css("foo::before")
         css2css("foo:empty::before")
         css2css('::name(arg + "val" - 3)', "::name(arg+'val'-3)")
         css2css("#lorem + foo#ipsum:first-child > bar::first-line")
         css2css("foo > *")
+        css2css("foo *.bar", "foo .bar")
+        css2css("foo > *[bar]", "foo > [bar]")
         # a leading universal selector is only redundant in a compound
         # selector
         css2css("* > foo")