roland
I am pleased to report this problem resolved, along with my previous reports of persistent wifi line dropping by Connman.
I spent some time on the www following the sound suggestions by Rokytnji about helping onesself to find solutions, and came across a warning to avoid having multiple network managers installed, which was my case. I uninstalled everything network related except Connman and Ceni, which for some reason is harmless in this context being merely a collection of scripts I think, ran a cold reboot, and have not lost my line since then. I will be monitoring progress but so far the author of this warning has an additional admirer. Thanks and best wishes!