There are instances in the earliest test where a sentence begins with a subordinate as-clause that is never completed. For a list, see under 1 Nephi 8:7; there I argue that most of these instances of as were in the original text. In some of these cases, the 1830 typesetter removed the extra as, as here in Helaman 7:10. In this particular case, the 1830 typesetter removed the as during proofing since in all the printed 1830 copies there is extra spacing in this line between the words for “therefore, Nephi had”; the extra word spacing in this line of type accounts precisely for an original as that was removed only after the initial typesetting.
David Calabro points out (personal communication) that here in Helaman 7:10–11 we may also have an original example of the Hebraistic and separating an initial as-clause from its following main clause. For discussion of this possibility, see under 1 Nephi 8:13 or, more generally, under hebraisms in volume 3. Under either interpretation, the critical text will restore the original as here in Helaman 7:10.
Summary: Restore in Helaman 7:10 the earliest extant reading (in 𝓟) with its initial as-clause; such usage can be found elsewhere in the earliest text.