You're going to need a bitcoin.conf file in order for Armory to be able to talk to Bitcoin-Qt.
If you want to use Armory and Bitcoin-Qt completely anonymously via Tor here is how I'd set it up:
1. Open Bitcoin-Qt, set it use your Tor proxy, then shutdown Bitcoin-Qt.
2. Configure Tor to create a hidden service that forwards to 127.0.0.1:8333 (Assuming you're running Tor on the same machine). Note the hidden service hostname.
3. Find the directory that contains peers.dat and wallet.dat. Delete peers.dat
4. In this same directory create a bitcoin.conf file with the following contents:
listen=1
dnsseed=0
bind=127.0.0.1:8333
tor=127.0.0.1:9050
externalip=.onion:8333
addnode=6hgmaxwellgpv2oe.onion:8333
addnode=divd5kytbhwdcyae.onion:8333
addnode=sojntcfkznvke6sl.onion:8333
addnode=l5ctgm66aaqimqta.onion:8333
addnode=b4zw2susxunomysu.onion:8333
5. Start Bitcoin-Qt with the "-onlynet=tor" command line option.
In this way you will only connect to hidden services and Armory will be able to communicate with Bitcoin-Qt.