Thank you, Labhrás. I suspected as much.

My impression is that lenition is with the Bracketed Construction. Ar son mhuíntir na hÉireann. But with the Unbracketed Construction: ar son muíntire na hÉireann. There are occasional examples of lenition with the Unbracketed Construction. There is fallaí thí scoile (quoting from memory) in Ua Laoghaire's Mo Sgéal Féin. Although that could be an editor's decision to add lenition there.

In one of his books:
Ba ró ghearr gur sgiúrd sé an dorus isteach chun muíntire an Leasa airís

Naofacht pobail Chorcaí móire Múmhan - is another example where pobail is not lenited.

EDIT: the quote is: ar an gcúinne thiar theas de mhapa na h-Éirean ar fhalla thíghe sgoile

We've been busy solving all the problems of the world.





Ah, I wouldn't have expected that to be the case with names somehow. Thanks for pointing out my mistake.



I'm a bit old fashioned, it seems I'll have to update my references.

And placenames, but I think everyone already knew that those were covered.