いつかしら

adverb

before one knows it; unnoticed; unawares

Describes something happening without the speaker noticing or realizing it. Derived from いつか知らぬ (lit. 'not knowing when'). Often used with past-tense verbs to indicate that a state or change occurred unnoticed.

See also: いつの間にか

• いつかしら雨あめがやんでいた。

  Before I knew it, the rain had stopped.

• いつかしら外そとは暗くらくなっていた。

  Unnoticed, it had gotten dark outside.