When I was in Italy, our local tour guide was asked what 'allora' meant by one of the people on the trip, because she said it so often. Her description of the word was this: "Allora...it is everything and nothing". You're right. It's "then" as much as it's "uuuhhh" and "well", etc.
I think 'allora' is one of those words that has the literal dictionary meaning (that DL may be using) and the more general meaning. I hear 'allora' being used pretty much like Americans use 'so', or 'well' or 'like', that is, as filler, rather than as a word with a specific meaning.
"Poi" and "Allora" have a temporal sense, but "Allora" has another meaning added to it: the logical consequence. Instead "Poi" only means after ....
Notice the difference:
you made something and "poi" you walked away. Here "poi" indicates the succession of events only. You are only saying that you are going to do something and after that you walk away, without stating any causal link between the two events. They can be completely unrelated. You're only saying that a thing happens after another one.
you made something and "allora" you walked away. Here there is a temporal succession but this is caused by the fact that the second action is a consequence of the first. The children broke the glass playing soccer and "allora" they walked away before being caught by teachers. Here the first action is the cause of the following action.
Eventually, there is another sense of allora. In some cases "allora" can have a pure temporal sense. It's when you are talking of a remote temporal situation, and in that case "allora" means : at that time. Mi sono sposato a 18 anni. Allora credevo nell'amore. I got married when I was 18 y.o. Allora (at that time) I was believing in love.
Being someone who thrives on word association to remember foreign words, I like your suggestion.
Also, Italians can have the tendency to use 'allora' as filler, sort of like Americans use 'so', 'like', 'you know.' A friend was taking an Italian immersion class in Florence and the instructor constantly used the word 'allora.' Finally, my friend asked her what 'allora' meant and she was puzzled at his question. When he explained, she said she had no idea she kept using the word.
Paolo, 'allora' might be used as a type of "speech mark", as something you say in order to keep talking, in order for the brain process stuff to go farther (on speech)?
In Portuguese we have at least two: 'então' and 'daí'. Both has temporal implications, and are used to connect parts of the speech, to keep on talking (and not allowing someone else to), to organize ideas and thinking, to begin a conversation, as a conclusive remark, multiple uses, just like 'allora'!
Maybe they're related in some way?