The former Cape Town All Stars midfielder has joined James Okwuosa and Marc van Heerden who have also joined The Buccaneers.
The trio arrive at Mayfair as part of swap deal that sees Nkosinathi Mthiyane, Donald Mokondolela, Justice Chabalala and Sello Japtha move the other way.
United boss Chippa Mpengesi has confirmed Lorch’s return to Pirates.
Lorch impressed during his loan spell with the Chilli Boys, prompting the Bucs technical team to give him a chance to stake a claim for a place in Augusto Palacios' side.