あるは

ある (aru, “to be, to exist”, rentaikei of the classical verb ari) +‎ は (wa, topic marker).[1] Arose from kanbun kundoku.

あるは • (aruwa) 

1. (obsolete) or, either; some ... and others

   Synonyms: あるいは (aruiwa), または (matawa), もしくは (moshikuwa)

   • 905–914, kana preface to the Kokin Wakashū

     …逢(あふ)坂(さか)山(やま)に至(いた)りて手(た)向(む)けを祈(いの)り、あるは春(はる)・夏(なつ)・秋(あき)・冬(ふゆ)にも入(い)らぬ種(くさ)々(ぐさ)の歌(うた)をなむ、選(えら)ばせ給(たま)ひける。

     … Ōsakayama ni itarite Tamuke o inori, aruwa haru natsu aki fuyu ni mo iranu kusagusa no uta o namu, erabasetamaikeru.

     All kinds of poems, such as …, the poems about coming to Ōsakayama and praying to the Tamuke no kami (traveler's guardian deity), or the poems which do not fall into any category of spring, summer, fall or winter, are chosen and collected.

あるは • (aru wa) 

1. (usually repeated in the form あるは…あるは… (aru wa … aru wa …), obsolete) some; sometimes; in some cases

   Synonym: あるいは (arui wa)