Definition of "For": A representation to a means. [http://dictionary.reference.com/browse/for] If you arraigned for a taxi, you scheduled a taxi, arraigned the means/mode/function/activity of taking a taxi. May be you told the taxi exactly where to go for the foreigner. If you only arraigned a taxi, you arraigned the mode, a taxi, at the simplest level. May be you just whistled or called a taxi and the taxi came. The taxi might not even know who to pick up. It just came because you told it to with no other instruction. To call for a meeting means that you have given the meeting some thought and perhaps have an agenda/schedule. If you call a meeting, again, this is at the simplest/lowest level. You might have just said "lets have a meeting" and the people attending would not know exactly what is to be discussed, for how long, nor by whom. The word "For" is a preposition. A preposition gives direction "that typically express a spatial, temporal, or other relationship, [means by]..." [http://dictionary.reference.com/browse/preposition?s=t]

Hi! :) Actually, in the examples you've given, there is little to no difference between the two. There can be a difference, but only when the "thing" in your sentence could be "arranged" as in repositioned, or "arranged" as in scheduled. Example: 1) I arranged for flowers to be delivered to her home. 2) I arranged flowers for the afternoon delivery. The first sentence means that you scheduled a delivery of flowers. The second sentence means that you actually positioned the flowers in a vase or basket for a delivery. Does that make sense?