Sorry to be so long in replying to this, when I changed my email address and updated it in Ancestry's system, it apparently doesn't change it on old queries, so wasn't informed of your response. Hope this finds you.
Elftmann is not a very common name, wonder if we hook up somewhere. I know that August was born in the town of Karolina (now Rychlik) just east of Poznan. His parents were born in Neudorf, just east of Karolina and died there.
August's father was Christopher who would have been born ca. 1780-1800.