I've said it before, but -
1) Pau is 21. Keepers are legendarily long-lived as far as playing careers relative to outfielders go - thus, he faces the prospect of sitting for Lloris for years on end if Hugo stays for a while, during most of the formative years when experience and regular playing time is key. Alternately, given Lloris' stature and long contract, any more immediate departure would presumably mean a big fee received for Hugo, which would only put pressure on the club to reinvest that money in a similarly high-profile goalkeeping signing - which would again restrict Pau's playing time, even when (if) Lloris does leave.
2) Pau can only be 'assessed' and 'acclimatize' to the league if he *plays* in competitive fixtures in England. He hasn't, at all - so I'm not sure what we've learned from having him lurking behind Lloris and Vorm. His personality? His ability to settle? The former could surely be assessed by the club prior to him coming here (or would otherwise be known to Poch from his time at Espanyol), and the latter surely doesn't justify the expense we're going to in terms of bringing him over here and paying his wages for a full *year* without actually owning him ourselves.
3) The quoted fee we would pay were we to make the move permanent is 6m quid - I find it hard to see Vorm leaving for a fee equivalent to that, so we'd actually be spending more on Pau than we would gain from Vorm's sale. Which, again, seems a bit strange to me given that, despite his year of hanging around Hotspur Way, he still wouldn't be acclimatized to the pace and strength of the English game (due to not having played), wouldn't count as a home-grown player or anything (and backup GKs are a bit of a 'gimme' in terms of filling HG slots) and wouldn't be likely to be our first-choice goalie ahead of Hugo given the factors above.