This is where I think it gets tricky... These will be Virgin Australia flights operated by Qatar airways.
The requirement for lounge access is that a flight is "marketed and operated by a Oneworld Airline".... Which indeed these flights will be (if you book the QR flight number).
The "operated by" rule is just another way of saying that the flight carrying the native flight number must be by a oneworld carrier. In this case, it's VA so I don't think these flight will be counted as oneworld flights.