My number one concern is always how clean my bed sheets are. Elsa's place is really clean (high standards clean). The apartment's situation is also perfect because you are close to the historic sights (considering you enjoy walking a little) and it's not in a noisy neighborhood so you can actually sleep like a baby.
Elsa herself is a great host, she sat with us and explained Lisbon's map to us when we arrived. She also gave us tips on where to eat and where to visit, how to go around the city (one of us even checked in earlier than 2 PM).
For those of you who like breakfast and need your morning coffee there is a cafe right on the street below the apartment called "Heim". It's really good. Brunch menu Green is delicious.
If you are looking for a place to stay, we recommend the apartment, the location and the host 100%. Please note that all the places we went to eat were vegan and vegetarian friendly. (one of us is vegan the other not).
We hope this is helpful.
Have a great time in Lisbon, it's a fantastic city.