If you ever want to use command line to manage BitLocker, there is a tool called manage-bde just for that purpose. If you have not used a command line tool before, remember to open an elevated command prompt first to type the command. Here are some examples:
Show the password for C drive
manage-bde -protectors -get C:
Turn on encryption on C drive using recovery password
manage-bde -on C: -RecoveryPassword
For detailed info about manage-bde, please see this TechNet documentation.