In this work, we present a robot-dialogue framework to handle sophisticated robot-initiated interaction. We introduce a robotic assistant equipped with a dialogue system in a household assistance context. To become a truly collaborative companion, the assistant is able to engage in a proactive conversation for task assistance. The system actions are triggered by the recognition of persons or specific objects. To evaluate our system, we conducted a user study with 17 participants in a laboratory environment where users were able to interact with the system via natural language. The results showed that the behaviour of the system was accepted and perceived as trustworthy by the users.