I think I found an answer to my own question, implementing what @mkennedy has kindly suggested. I used this website (http://www.geoplaner.com/) to get the latitute extent of my area of interest by getting the latitude of two points: A (North) 46 degrees N, B (South) 30 degrees N. The exent is 46-30=16 degrees. 16 divided by 6= 2.7. Therefore, the Standard Parallel 1 (the southernmost) should be equal to 30+2.7= 32.7. The Standard Parallel 2 (the northernmost) should be equal to 46-2.7= 44.7. I entered those Standard Parallel values into the relevant fields of the ArcMap's Europe Lambert Conformal Conic data window.