You want
Taxes Consolidation Act 1997 s. 604(5)(b):
... any period of absence throughout which the individual worked in an employment or office all the duties of which were performed outside the State ... shall be treated as if in that period of absence the dwelling house ... was occupied by the individual as his or her only or main residence ...
So, if your current employer seconds you to work abroad, no problem.
But, it seems to me, if you quit your Irish job, take up a new job in Umbrellastan and go to Umbrellastan to do that job, you're still OK (provided the other conditions are satisfied, of course; you have to actually reside in the Irish property both before and after your stint in Umbrellastan.
But. . .
You have to stay abroad only while actually doing the Umbrellastani job. If you quit your Irish job, go to Umbrellastan and hawk yourself about at hiring fairs until you find Umbrellastani employment, you haven't been working in Umbrellastan throughout the period of absence. Similarly if, at the end of your stint you take three months out to tour the soukhs and hashish-houses of Morocco on the way home, you haven't been working in your foreign employment throughout the period of absence.
And here's the thing: s. 604(5)(b) doesn't give you relief for that part of a period of absence during which you were working abroad; it only gives you relief if you were working abroad
throughout the period of absence.
I don't know what Revenue practice here is. Presumably they'll allow you some leeway at each end of the Umbrellastani gig to pack your bags, make the journey, etc.; perhaps to find a job on arrival, if you haven't sorted one before travelling; perhaps even a little holiday on the way out or home. But I don't know how much leeway. And I think you'd want to look into that (which is to say, pay an experienced tax adviser to look into that) before you actually commit to anything. Because it seem to me that if you fall on the wrong side of whatever line the Revenue draw, the consequence would be loss of the relief for the entire period of absence.
I could be wrong. Revenue may as a matter of practice agree to treat your period of absense as two periods, one for working and one for doing the three-months-in-Morocco thing, and to grant you relief for the first period. But if you want to know for sure, you're going to have to pay somebody more competent than me to tell you.