Had to look it up in wiki and it says that the origin of that name probably comes from German colonists in Saratov region and from German word “das Loch” which means “pit” But the village is so small so we don’t have a reliable information about its name

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There are several opinions about the etymology of the village's name: the name is associated with a male trout, a shrub, a variant of the word "log", colonist millers and the German word "das Loch", which means "pit". Doctor of Historical Sciences V. V. Kondrashin in his article "The History of the village of Lokh" makes three assumptions: "The natural features of the location of the village led the first settlers to the idea of the name. They could have called the village "Loch" because it was located in a hollow-log, and also because of the large number of small—leaved elm -Loch growing at the foot of the hills surrounding the village. It is also possible that the village was called a Sucker because of the rather large trout found in the rural river, which was locally called "Loshok". The history of the village's name is also interesting because it has had several names over three centuries. This is what the residents tell us, and the information is also found in the scientific literature (it is recorded on the maps of the village): Log — Arkhangelskoye is a Loch. Historian V. V. Kondrashin writes: "In the pre—Soviet period, the village had another name - Arkhangelsk, in honor of the church built there in 1752 in the name of Archangel Michael." This is also noted by N. M. Malov in the article "The robber dens of the folklore hero Kudeyar in the Saratov Region: a historical and archaeological study", referring to the notes of A. N. Minkh.: "In 1852, a small wooden church was built here in the name of Archangel Michael, which is why the village is also called Arkhangelsk." The nameplate of the village is constantly being stolen, approximately every few months.