How to get the inner boundaries of a block

[Jens Schmidt]

Triggered by a recent question here on `org-in-src-block-p' and a
current need: Is there a function already available that returns
the *inner* boundaries of an arbitrary block element?

For the element corresponding to the block below:

#+begin_verse
^A  foo
  bar
  baz^B
#+end_verse

that function would return, for example, the pair of positions (A . B).

Currently, I use org element properties and some combination of
save-excursion, forward-line, and skip-syntax-*, but I thought this
could be something which is available already.  A cursory search hasn't
brought up anything, though.

Thanks                                                          Jens