The software requirements elicitation from stakeholders has been stated as a key activity influencing strongly on quality of specified requirements and, therefore, of the final development product. For this raison, is undoubtly the necessity to dispose clear guidelines to drive the interrelationship with the owners of the domain information and the needs that require solutions. This work focuses on the model of the elicitation considering the influence of the contextual agents of the process, such as: elicitor, who drive the activity; informant, who possess the relevant information; problem domain, characteristics of the problematic to tackle; and process, characteristics and restrictions of the activity itself. The article analyses the dynamic that relates these factors to select the technique to use in each elicitation session. Finally, the work contributes with a time model of the process and with the representation of the main casuistic of elicitation process.