def split_qualified(fqname):
    """
    Split a fully qualified element name, in Clark's notation, into its URI and
    local name components.

    :param fqname: Fully qualified name in Clark's notation.
    :return: 2-tuple containing the namespace URI and local tag name.
    """
    if fqname and fqname[0] == '{':
        return tuple(fqname[1:].split('}'))
    return None, fqname