installing qBittorrent
Use sudo add-apt-repository ppa:qbittorrent-team/qbittorrent-stable -y && sudo apt-get update && sudo apt-get install qbittorrent -y to install from Ubuntu PPA.
Personal experience
Tested in Kubuntu 17.10 and Lubuntu 18.04.
licensing
No rights reserved: CC0 1.0.
prior work
The bulk of the installation script was introduced to me by the qbittorrent-stable PPA page on Launchpad.