I have been having a similar issue, where I am trying to play Minecraft on a network where Mojang's servers are blocked by the firewall. In the past, I've been able to play offline in these situations, but when I tried using the latest version at the time (1.8.3), it kept trying to download files, and would fail because they were blocked or my wireless card was disabled, and it would fail to start.
I tried making a new profile and using an older version of Minecraft that had once been fully downloaded on my machine on an unblocked network (1.8.1). I forced the profile to use this version of Minecraft, and I successfully was able to open my Minecraft client without downloading any other software, such as MCPatcher (which I also cannot download because the MCForums are blocked here).
It seems the Minecraft client requires whatever version you are using to have ALL files for that version downloaded locally to the machine. Whenever I tried opening 1.8.3, it kept trying to download files related to Minecraft Realms, which I don't even need for playing offline, or so I would think.
For future reference purposes, my client output can be found here for the failed attempts.