There's an interplay between the stark sudden and the slow burn throughout this movie. We begin with an immediate Immersion into the drift of Casey's life and his sexuality which has driven his path this far. He's taken off away from his birthplace after a rejection of him by his married lover, an unexpected tragedy, and his family and community virulence afterwards. And, he works his way along the edges of people in activities out in the public towards the ocean where he tries to finish his part in it and life. He is unsuccessful. Rejected by the sea, Casey then drifts back into Sydney where he quickly finds and joins a small orgy in an unofficial residence. The afterglow of he and its prime mover, Tib, leads to the next in the movie's series of latent simmerings - a number of gig economy small jobs and handyman tasks while also falling for this roommate. The two of them eke out an existence together until Tib faces a deeply personal rejection and responds as he seems he is wont to do. Tib's reaction, in turn, thus feels to Casey as yet another rejection and his self-defense destructive impulses sets him off adrift once again until he finally wakes up that this is not the life he wants for himself or Tib.
You may not appreciate this sort of sloshing meter. You may likewise either be repulsed by Lonesome's edginess which, it seems to me, is part of the current Australian motion picture (and especially its LGBTQ+) storyline landscape. The lonesomeness of this movie, however, is manifested through both, not only of Tib and Casey, but also of those they come in contact with and interact with throughout its storyline.