A noun appearing as ᴱQ. orosta “ascension” in the Qenya Lexicon and Poetic and Mythological Words of Eldarissa of the 1910s, based on the early root ᴱ√ORO (QL/70). The Qenya Lexicon also had an unaugmented variant rosta under the root ᴱ√RŌ (QL/80). Early Noldorin word lists of the 1920s instead had ᴱQ. orosta as equivalent to ᴱN. oroth “impetus, speed, haste, rash courage”, derived from primitive ᴱ✶orotse (PE13/151); see ᴹQ. orme for discussion.
Neo-Quenya: Since √RŌ/ORO “rise” survives in Tolkien’s later writings, I would retain ᴺQ. orosta “ascension” for purposes of Neo-Quenya.
The Qenya Lexicon of the 1910s had a verb ᴱQ. rōna- “arise, rise, ascend” under the early root ᴱ√RŌ [or ᴱ√ROHO], an inverted variant of ᴱ√ORO (QL/80). It had unusual past forms roa or roi. A similar verb ᴱQ. rosta- appeared in the Early Noldorin Dictionary of the 1920s, equivalent to the ᴱN. rhosta- or amrosta- under the entry ᴱN. amrost “rising” (PE13/159). All later (and many earlier) Quenya verbs for “rise” seem to be based on √OR, such as orya- or orta-, though hints of the inverted root can be seen in later writings with occasional irregular past forms like ronte (PE22/115).