I'll see what I can find on her.
California marriage and death records aren't online, so no way to verify when she died. Her birth record is available and shows she was the twin of Elsie May. She was still alive when the 1920 census was taken, listed as Evelyn M. Sorensen. I did not find her in any subsequent census under Evelyn, Evaline or any other spelling, so she must have died between 1920 and 1930. You can apply for a death certificate from San Francisco.
The only way to learn when and how Evaline died is to get her death record from the San Francisco county clerk. There is an abbreviated death index (that doesn't list cause of death), but it doesn't begin until 1940. You can read more here:
California is one of many states that makes very little available online to researchers. A family member (with identification) has to pay for the certificates.