When dictating stories on his deathbed some 50 years ago, my great grandfather passed along to my great aunt the idea—which he got from his grandfather, a West Prussian émigré—that our last name, Strehlke, means arrow man. Many years later, my father stumbled upon the Russian word стрелка, which, if we're not mistaken, means arrow, and sensed a connection. Though I don't speak Russian, I did a little looking online and was unable to uncover the etymology of стрелка. I'm wondering if one of you can help me find the origin of the word—I have no reason to believe that my family or our name is Russian, and I'd be particularly interested in any reason why the word or its root might be linked to a Germanic language.
Стре́лка indeed means ‘arrow’ in sense of ‘line with arrowhead’, ‘needle / pointer [of an instrument]’, ‘hand [of a watch]’ and so forth. It is a diminutive of стрела́, which mainly stands for ‘arrow’ as a projectile. The modern German word ascending to the same PIE root is Strahl /ʃtʀaːl/ (beam, ray).
As for your name, it’s not Russian of course, but suffix -ke in combination with place of origin (Prussia) however quite clearly hints for Slavic roots.
The Russian word "strelka" (I use the transliteration only because there is no trouble to translaterate this word, as all used here letters have more or less exact Latin equivalents) is a deminutive from "strela". The first word is used to denote an arrow pointer, a geometric arrow, the later is used to denote the projectile.
I doubt that a surname could originate from a geometric arrow or pointer, but there is also a related Russian word "strelok" which means a shooter (which in turn originates from "strela"). I suggest that your surname can originate from this word.
The word is cognate to Lithuanian strēlà "arrow", Latvian "strę̀la" "arrow", "stream", "strip", Old English "strǟl" "arrow", German "Strahl" "beam, stream".
Further etymology is uncertain.