Arte Murano is a generic term, and 'Lavorazione' is referred to in the 'Labels' thread (see Sticky at top of the forum page). From what I understand, this is probably Murano, but could still be imported from Eastern Europe or China and resold on Murano.
Because Murano (the island) is identifiable with quality art glass production, the term is often found (and used and abused) around the world. Chalet Glass in Canada, for example, where called Murano Glass in the early 1960s. There are other examples, with ICET being one notable example that they probably justify by originally employing Muranese workers (or is ICET owned by former workers?)