I think Okrand simply meant that ‘ar cannot follow a noun with a plural suffix, which is how I’ve always understood it.

Examples of ‘ar following a grammatically singular mass noun where it’s translated “how much”:

  nIn 'ar wIghaj

How much fuel do we have left?  TKD/CK/PK

  Huch 'ar DaneH?

How much money do you want?  TKD

  Dochvetlh DIlmeH Huch 'ar DaneH

How much do you want for that?  TKD

Examples of ‘ar following a regular count noun without a plural suffix where it’s translated “how many”:

  Haw'pu' yaS 'ar

How many officers fled? TKD

  mughoS 'avwI' 'ar

How many guards are coming? CK

There were fewer examples than I expected – and none from the paq’balth AFAIK.

--Voragh

From: Felix Malmenbeck

In TKD §6.4, this is written of the word 'ar:

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Finally, 'ar how many? how much? follows the noun to which it refers. It can never follow a noun with a plural suffix
(-pu', -mey, -Du'; see section 3.3.2).

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I've always taken this to mean that a noun followed by 'ar is grammatically singular, and so we must say, for example, qachvam Dab nuv 'ar?, rather than *qachvam luDab nuv 'ar?*.

However, it now strikes me that there is another possible interpretation, namely that while the noun followed by 'ar is never marked with a plural suffix, it could still be considered grammatically plural, and thus allow for sentences such as *qachvam luDab nuv 'ar?*.

Unfortunately, the canonical example sentences we have using 'ar don't really shine much of a light on this. The only example I've found  that uses a number-specific verb prefix to go with the NOUN + 'ar construct is nIn 'ar wIghaj. ("How much fuel do we have?") However, this example is of limited use, as the quantity of nIn ("fuel") is a presumably continuous, rather than discrete; while we would normally treat nIn law' and nIn puS as singular, we would treat nuv law' and nuv puS as plural.

Can anybody think of any examples that could help to resolve this matter? Or is there an unofficial but commonly accepted answer?