I did a quick look on that Taylor-Hobson cine lens...apparently those were pretty popular for shooting Hollywood-produced Technicolor films back in the 1940's, and were rather high-end lenses. The flange-to-film distance is supposed to be,I think, 51.97mm or 55mm for that lens's native mount, so it would seem that with your Canon's 44mm flange-to-sensor register distance that the lens needs an extension tube to achieve normal, full range of focus. I don't know anything about the Arriflex mount,really.
Somebody on one thread suggested that a T2 adapter is 55mm in diameter and might/would accept an Arriflex mount. Might that be true?
I did see a similar vintage lens of the identical make and f/stop on eBay, rigged with a Canon 11-25 variable extension tube and an M42 thread mount on the back of that, and the lens was priced at around $1599, plus $200 for the extension and mount adapter...the seller said that with the extension tube, the lens achieved it full range of focusing, from close-up, to infinity, when used with an adapter on Canon.